Research on the genetics and physiology of Salmonella typhimurium will deal especially with three topics: (1) Lipopolysaccharide and other components of bacterial surface; especially mapping of rfa genes, determining structure of LPS core, determination of nature of defects in "part-rough" mutants, and testing of effect of such mutations on (mouse) virulence. (2) Genetics and physiology of motility and chemotaxis, especially correlation of relevant genes in Salmonella and Escherichia, attempt to identify products of fla (flagella production) and che (chemotaxis) genes. (3) Genetics and behavior in S. typhimurium of R (antibiotic resistance) and colicine factors, especially mapping of genes of plasmid R46 which determine its UV-protecting and mutator properties. BIBLIOGRAPHIC REFERENCES: Salmonella typhimurium mutations conferring resistance to Felix O phage without loss of smooth character: phage attachment and immunochemical and structural analyses of lipopolysaccharides. Lindberg, A. A. and Svensson, S. (1975) J. Gen. Microbiology, 87:11. Integration, at hag or elsewhere, of H2 (Phase-2 flagellin) genes transduced from Salmonella to Escherichia coli. Enomoto, M. and Stocker, B. A. D. Genetics (in press).